The present invention concerns a water-raising pump for drawing water in a ground water table, which pump comprises a tube connecting the surface to the water table to be pumped, a rod carrying the pistons, which is connected to a drive mechanism installed at the surface for imparting to the rod a reciprocating pumping motion.
In general, such pumps are intended to be installed in places benefiting from little technical assistance, and must also be as simple and robust as possible. However, one of the great difficulties in the driving of water-raising pumps is the guiding of the rod carrying the pistons. The guiding must be as centred as possible relative to the draft tube in order to reduce friction to a minimum and thus facilitate the operation of the pump while reducing the wear.
In this type of pump it is likewise necessary to reduce to their simplest form the guide means necessary for the rod, since these guide means, at least those which are on the outside, close to the drive source, are exposed to dust, sand, etc. which reduce or indeed impair the guiding characteristics. This in turn has its effect on the correct operation of the installation and its reliability.
The aim of the present invention is to remedy some of the drawbacks of the known water-raising pumps, and proposes to provide a drive and guiding means which is as simple as possible, subject to little wear even in very difficult operating conditions such as in an atmosphere charged with sand or dust, and which allows very regular and smooth driving of the pumping rod.
To this end, the invention concerns a water-raising pump of the type defined above, characterized in that the mechanism comprises:
two identical toothed wheels, mounted on axes that are symmetrical relative to the trajectory of the rod carrying the pistons,
meshing in each other so as to rotate in opposite directions, a motive unit connected to at least one of the wheels to drive it in rotation,
two identical connecting rods, each connected to the head of the rod and to a point of articulation borne by each toothed wheel, in symmetrical positions, in order to be driven in symmetrical motions relative to the trajectory of the rod in order to guide and drive the rod and its pistons.
The symmetrical arrangement of the drive means according to a symmetry relative to the axis of the rod makes it possible to ensure the guiding of the pump rod in the plane of symmetry and to maintain the head of the pump necessarily in this plane of symmetry.
The drive device is extremely simple and, once adjusted, it can no longer lose its adjustment, at least with regard to the geometry of the trajectory of the rod.
Moreover, owing to the simplicity of the means employed, the mechanical output is very high, since friction is reduced to a minimum.
The stroke of the rod is adjusted by means of the lever arm of the point of articulation of one end of each connecting rod relative to the centre of rotation of the toothed wheels.
Such a pump can be driven by a crank, manually, or by a motor, especially an electric motor fed by a solar cell or by a generating set in the case of an electric motor.
According to other advantageous features of the invention:
one of the toothed wheels includes or constitutes the inertia flywheel,
the connecting member between the two connecting rod big ends and the head of the rod receives the articulations of the rod head and the two articulations or fixing points of the two connecting rods,
the connecting rods can operate in pull or in push mode.
Finally, the connection with the drive device is a belt or a chain.
According to other advantageous features of the invention:
the connecting rods are connected to the rod by way of levers pivotally mounted on pivots,
the connecting rods are connected to the toothed wheels by way of levers mounted on pivots co-operating with the toothed wheels through a connection with rollers and slides, the slides being provided in the levers and the rollers in the form of pivots carried by the toothed wheels.
Finally, such a machine, used as a pump driven by a motor, may also operate as a motor supplied with pressurized fluid.